We have established that to enhance the effectiveness of the EU sanctions regime it is necessary to ensure the sanctions’ compliance with international law and communicate the underlying rationale. The high evidentiary standards established by the Court of Justice of the European Union in other types of regime (e.g. terrorist sanctions) suggests that a similar approach will be adopted in the case of the cyber sanctions regime. Does this mean that absolute certainty regarding attribution is the only way forward? This chapter introduces another concept of international law – the principle of due diligence – and demonstrates how it might become a powerful tool in making the EU’s case for cyber sanctions even stronger. Like the gravitational force between all masses in the universe, the concept of due diligence brings to the fore the question of interdependence between different actors. The principle of due diligence also provides answers to two important questions about the ‘laws of gravity’ in cyberspace: (i) do the capacities and resources of a country determine the level of its responsibility for harm originating from its territory (gravitational force)?; and (ii) how does the level of interconnectedness between states influence their rights and obligations vis-à-vis each other (gravitational attraction)? In other words, to what extent are states responsible for cyberattacks originating from their territory ?